A movie I watched in late 1980's. Its an erotic thriller. Very specific scene. A man ( maybe detective ) meets a woman ( reporter ??? ) He takes her to a sex club. There is a circle with naked people. In the center is a couple having sex. The movie has orgies, and one point she is used by a group of men . The male that took her just watches. Not a porn, maybe soft core or erotic thriller. Could be foreign , it takes place in a large city. I think the woman is investigating something.